1. Field of Invention
The human immune system, although highly complex and at present imperfectly understood, is presently considered to have two principal aspects: (1) humoral immunity, which is mediated by circulating antibodies; and (2) cell-mediated immunity which is mediated by lymphoid cells. Humoral immunity can be transferred from an immune donor to a non-immune recipient by means of serum immunoglobulins. Such serum-mediated transfers result in immune responses that are manifest almost instantly. Cell-mediated immunity can be transferred by means of peripheral blood leukocytes, or preparations thereof; such immune responses develop over a period of several hours. The present invention concerns cell-mediated immunity.
A typical manifestation of cell-mediated immunity is the delayed hypersensitivity ("DH") skin reaction. A DH skin reaction is observed when the appropriate antigen is injected subcutaneously. Within 24 to 48 hours, local inflammation (erythema) and a swelling and thickening (induration) are observed in a sensitive individual. The degree of sensitivity may be measured by the size and severity of the reaction. The DH reaction also presents characteristic histological findings--specifically, perivascular infiltration of lymphocytes and monocytes in the inflamed area. The cells seen at the site of a DH reaction are derived from the peripheral blood leukocyte population.
The mechanisms of cell-mediated immunity are as yet incompletely understood. It is known that the cells which mediate the response are capable of responding in a variety of ways to a challenge from an antigen. These responses include: proliferation of cells bearing specific sensitivity to a given antigen; the induction and multiplication of cells mediating a variety of immune functions, including antibody production; and reactions against foreign cells and tumors.
The present invention relates to the discovery of (1) methods for extracting "amplifiers" of the immunity system, which are isolated from dialyzed extracts of leukocytes, and (2) the amplifiers themselves that are so extracted. These amplifiers profoundly affect the quality and quantity of cell-mediated immunity responses; are useful in the treatment of a variety of clinical conditions characterized by inadequate reaction to a specific antigen; and are useful in the alleviation of certain anergic conditions.
Much of the background relevant to the instant application is found in the specification of copending application Ser. No. 441,432, which is presently scheduled to issue as U.S. Pat. No. 4,468,379, on Aug. 28, 1984. That application (hereinafter referred to at times as "the cited copending application") is a continuing application based on then copending application Ser. No. 256,886, filed May 6, 1982, which was a continuing application based on then copending Ser. No. 149,737, filed May 14, 1980.
2. Prior Art
The prior art in this field is discussed in the cited copending application, and that discussion is incorporated herein by reference.
Transfer factor. Much of the prior art concerns the so-called "transfer factor," a product very different from the subject matter of this invention and in some ways antithetical in concept thereto. When a "transfer factor" preparation is made from leukocytes of a donor known to be sensitive to a given antigen, and the preparation is injected subcutaneously into the skin of a recipient known to be insensitive to the given antigen, and subsequently the recipient is challenged with the given antigen--a DH response is observed. Normally, the recipient, in the absence of the injected "transfer factor" preparation, would have been unresponsive to the challenge from the given antigen.
The "transfer factor" phenomenon is believed by the inventor to be demonstrable in human beings only with regard to substances derived from human beings (although some researchers have claimed to derive from animals "transfer factors" that could be used in human beings). Progress in fractionating and characterizing "transfer factor" has been impeded by the lack of associated structural or chemical criteria and by the fact that the phenomena observed after fractionation are often qualitatively different from the phenomena induced by the original dialysate. Although the term "transfer factor" appears in literature as applied to fractionated preparations, and as monitored by criteria other than a DH skin response, it is unclear whether in such terminology the term "transfer factor" is indeed used to refer to a single biochemical entity or to an activity that represents a single biological function, or rather to refer to a mixture of materials of various kinds. Such dialysates may, and the inventor believes that they typically do, contain various different molecules and entities.
Some of the work in this field was summarized and commented on by A. Uotila, in Transfer Factor and Other Immunological Activities of Human Leukocyte Dialysate and Other Dialysates of Mammalian Tissues (1979). Uotila's monograph indicates that preparations of so-called "transfer factor" may contain a large variety of substances. Uotila suggested that an "augmenting activity" can be derived from dialyzable leukocyte extracts in guinea pigs, but did not disclose whether this is one or several different materials or activities, or if the latter, how to separate them from one another. As explained in the specification of the cited copending application, the inventor believes that this monograph is of interest primarily because it teaches away from the disclosure of the copending, and also the instant, patent application.
Comparison of Transfer Factor and Modulators of Cited Copending Application
Modulators. The cited copending application and also the instant invention relate to what the inventor terms "modulators" of the human or animal immune system. A "modulatornn" as therein and herein defined is, in general terms, any substance or material that has a "modulator activity."
To have a modulator activity is to affect a response, whether direct or indirect, of an animal or human body, portion thereof, or matter taken therefrom, to the reintroduction of antigens to which said body has been previously exposed, where such response is specifically attributable to the function of the immunity system of said animal or human.
Substances having general bodily effects that may also include effects on the immune response are not subsumed within the term "modulator," as herein defined. Such modulators manifest their activity in a DH skin reaction test, and therefore appear to exert their primary effect on the cell-mediated immunity system. It will be understood, however, that such modulators have broad effects on the entire immunity system, and may also affect the humoral immunity system.
Amplifiers. An amplifier is a modulator that amplifies the onset, or rate or intensity, of the immune response. Hence, it may be said that "amplifier" material is that modulator material characterized, in general terms, by "amplifier" activity, i.e., the production of a greater than normal immune response (faster or stronger, or both) in a sensitive recipient, following injection of an antigen to which the recipient is already sensitive. The instant application primarily concerns amplifiers, also termed at times "immunoamplifiers," and methods of extraction thereof.
The term "amplifier" is used, at times herein to refer to both genus and species. That is, "amplifier material" may be a mixture of amplifier species. It may also contain extraneous material, which is without amplifier activity. Moreover, it is by no means suggested that any single amplifier species extracted by the methods of the invention is a single molecular species rather than a mixture of molecules. Amplifier material is considered useful in the treatment of anergic conditions and conditions of immune deficiency, both local and systemic, as in the Acquired Immune Deficiency ("AIDS") Syndrome and related conditions.
It will be understood that "transfer factors" are not amplifiers, as defined above, since the effect of a transfer factor is observed in a recipient who has not previously been exposed to a given antigen, while the effect of an amplifier is observed only upon or following reintroduction of an antigen to which the recipient was previously exposed. Furthermore, transfer factor effects are specific with respect to a given antigen, but amplifiers exert non-specific effects with respect to any antigen to which the recipient was previously exposed.